The cast and crew from the final instalment of The Hobbit trilogy showed off the first trailer for the film at pop-culture event Comic-con.
Director Sir Peter Jackson also revealed he has been hanging out at the geek convention disguised in a black and white jester outfit.
He took to the stage for a panel presentation in front of an audience of 6500 people.
Comedy Central host and Tolkien fan Stephen Colbert moderated the panel, dressed in the costume he wore in a cameo in the last Hobbit film, the LA Times reported.
Joining Colbert and Sir Peter on stage were actors Cate Blanchett, Andy Serkis, Benedict Cumberbatch, Lee Pace, Luke Evans, Elijah Wood, Graham McTavish, Evangeline Lilly and Orlando Bloom, along with the director's longtime collaborator Philippa Boyens.
Sir Peter promised the The Hobbit: The Battle of Five Armies, which is being released on December 17, will offer action and heartstring-tugging moments.
The killing off of characters was a chance to do something ugly, powerful and emotional, he said.
A competition was announced for 75 double passes for a one-week tour of Middle Earth locations across New Zealand.
The 75 ardent fans, each taking a friend, will finish their tour with a private screening of the final film with Sir Peter.
"One of the joys of making the Lord of the Rings and The Hobbit films was discovering Middle Earth right here in my home country of New Zealand," Sir Peter said.
"[It is] a place that has sparked my imagination since I was a kid and picked up a movie camera for the first time."
Fans will land in Auckland, visit Middle Earth locations including a private tour of central character Bilbo Baggins's home of Hobbiton in Matamata, before the screening in Wellington.
The search for the "ultimate fans" begins on August 25.
Wellington's Weta Group also has a big presence at the convention to mark 20 years of creative work, including on Sir Peter's blockbuster films.